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G L Trick

Publications and source records attributed to G L Trick.

41 records · Page 3Linked to original sources

Confrontation visual field techniques in the detection of anterior visual pathway lesions.

The accuracy of a variety of finger and color confrontation tests in identifying chiasmal and optic nerve visual field defects was assessed in patients whose field defects had been established beforehand by a conventional achromatic kinetic technique on the Goldmann perimeter. Kinetic and static finger confrontation methods identified an average of 42% of the 28 chiasmal hemianopic defects. False negatives included eyes with hemianopias complete to the largest (V4e) Goldmann isopter. False positives (average, 15%) occurred in eyes containing nerve fiber bundle defects with borders that fell near the vertical fixational meridian. Kinetic and static color confrontation techniques were 78.6% sensitive to hemianopias. Accuracy did not differ significantly whether the red target was presented kinetically or statically against the tangent screen, projected on the Autoplot screen, or held in the examiner's hand without attention to background. False positives (average, 23%) were slightly greater than with finger confrontation methods and occurred not only in eyes with nerve fiber bundle defects but also in eyes with no defects in reference visual fields. Finger confrontation identified 11% or fewer of optic nerve field defects, while some color techniques detected as many as 31 1/3%. There were no false positives.

Hemianopsia↗

Heterochromatic additivity and the CFF response.

The validity of the heterochromatic additivity principle (Abney's Law) was examined using bichromatic combinations of test wavelengths adjusted to equal luminance by a CFF technique. Additivity failures qualitatively similar but smaller than those resulting from foveal threshold, incremental threshold, or direct brightness matching techniques were evident for a number of bichromatic combinations. These results suggest that the CFF response is influenced, to a small degree, by the activity of opponent-color channels.

Color↗

Improved electrode for electroretinography.

Corneal electrodes useful for clinical electroretinography require topical anesthesia, interfere with vision, can abrade, and are not well accepted by most children and many adults. A low mass conductive thread, corneal (DTL) electrode is described and comparatively tested against the Burian-Allen electrode. The DTL electrode was found to have few of the limitations of the hard contact lens electrode. Furthermore, the DTL electrode signal quality was comparable to that of the Burian-Allen electrode and provided less between-patient variability.

Adult↗

Guidelines for basic pattern electroretinography. Recommendations by the International Society for Clinical Electrophysiology of Vision.

The pattern electroretinogram is a retinal response that can be evoked by viewing an alternating grating or checkerboard. It is receiving increasing clinical and research attention because it can provide information about inner retinal cells and the macula. However, clinicians may have trouble choosing between different techniques for recording the Pattern electroretinogram that have been described in the literature. The International Society for Clinical Electrophysiology of Vision has prepared guidelines for a basic pattern electroretinogram recording procedure to aid new users in obtaining reliable responses and to encourage more uniformity among existing users.

Electroretinography↗